Synergistic extraction of rare earths(III) from chloride medium with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 and di-(2-ethylhexyl)-2-ethylhexylphosphonate

The synergistic effect of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 (HPMBP, HA) and di-(2ethylhexyl)-2-ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE (III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y3+, and taking Yb3+ and Y3+ as examples, RE3+ is extracted as RE(OH)A(2).B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change Delta G (-17.06kJmol(-1)), enthalpy change Delta H (-35.08kjmol(-1)) and entropy change Delta S (-60.47JK(-1)mol(-1)) for Y3+ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements.

Extraction of rare earths(III) from nitrate medium with di-(2-ethylhexyl) 2-ethylhexyl phosphonate and synergistic extraction combined with 1-phenyl-3-methyl-4-benzoy l-pyrazolone-5

The extraction of trivalent rare earths ( RE) from nitrate solutions with di-(2-ethylhexyl) 2-ethylhexyl phosphonate (DEHEHP, B) and synergistic extraction combined with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP, HA) were investigated. The extraction distribution ratios demonstrate a distinct "tetra effect," and Y lies between Tb and Dy when DEHEHP is used as a single extractant for RE. According to the corresponding separation factors (SF12) for adjacent pairs of rare earths, it could be concluded that DEHEHP could be employed for the separation of La from the other rare earths, and Y from light rare earths. The present work has also found that mixtures of HPMBP and DEHEHP have an evident synergistic effect for RE(III). Taking Y( III) as an example, a possible synergistic extraction mechanism is proposed. The enhancement of extraction in the binary system can be explained due to the species Y(NO3) (.) A(2) (.) HA (.) B formed. The synergistic enhancement coefficients ( R), extraction constants, formation constants and thermodynamic functions of the reaction were calculated.

Crystal structure and DFT studies of a triazole derivative: 4-(2-hydrobenzylideneamino)-3-(1,2,4-triazol-4-yl-methyl) 1H-1,2,4-triazole-5 (4H)-thione

A novel triazole derivative 4-(2-hydrobenzylideneamino)-3-(1, 2, 4-triazol-4-ylmethyl)-1H-1, 2, 4-triazole-5 (4H)-thione(1) was synthesized and characterized using elemental analysis, MR, and H-1 NMR, and its crystal structure was determined via X-ray single crystal diffraction analysis. Crystal data: monoclinic, P2 (1)/c, a = 0.83335 (9) nm, b = 1. 49777 (16) run, c = 1. 14724 (12) nm, beta = 107. 990 (2)degrees, D = 1. 470 Mg/m(3), and Z = 4. The geometries and the vibrational frequencies were determined using the density functional theory(DFT) method at the B3LYP/6-31G* level. To demonstrate the accuracy of the reaction route of compound 1, one of the important intermediates was also tested using the same method. The structural parameters of the two compounds calculated using the DFT study are close to those of the crystals, and the harmonic vibrations of the two compounds computed via the DFT method are in good agreement with those in the observed IR spectral data. The thermodynamic properties of the title compound were calculated, and the compound shows a good structural stability at normal temperature. The test results of biological activities show that it has a certain bactericidal ability.

Analysis of carbohydrates in a tibetan medicine using new labeling reagent, 1-(2-naphthyl)-3-methyl-5-pyrazolone, by HPLC with DAD detection and ESI-MS identification

A new labeling reagent, 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP), coupling with liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS) for the detection of carbohydrates from a famous Tibetan medicine is reported. Carbohydrates were derivatized to their bis-NMP-labeled derivatives. The method, in conjunction with a gradient elution, offered a baseline resolution of carbohydrate derivatives on a reversed phase Hypersil ODS-2 column. The carbohydrates such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose, and fucose could be successfully detected by UV and ESI-MS. Derivatives showed intense protonated molecular ion at m/z [M+H]+ in positive ion mode. The mass to charge ratios of characteristic fragment ions at m/z 473.0 could be used for the accurately qualitative identification of carbohydrates; this characteristic fragment ion was from the cleavage of C2-C3 bond in the carbohydrate chain giving the specific fragment ions at m/z [MH-CmH2m+1Om-H2O](+) for pentose, hexose, and glyceraldehydes, and at m/z [MH-CmH2m-1Om+1-H2O](+) for alduronic acids, such as galacturonic acid and glucuronic acid (m=n-2, n is carbon atom number of carbohydrate). Compared with the traditional 1-phenyl-3-methyl-5-pyrazolone (PMP) reagent, currently synthesized NMP show the advantage of higher sensitivity to carbohydrate compounds with UV and ESI-MS detection.

Detection of carbohydrates using new labeling reagent 1-(2-naphthyl)-3-methyl-5-pyrazolone by capillary zone electrophoresis with absorbance (UV)

A novel labeling reagent 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP) coupled with capillary electrophoresis (CE) with DAD detection for the determination of carbohydrates has been developed. The chromophore in the 1-phenyl-3-methyl-5-pyrazolone (PMP) reagent is replaced by naphthyl functional group, which results in a reagent with very high molar absorptivity (epsilon(251nm) = 5.58 x 10(4) L mol(-1) cm(-1)). This pen-nits NMP-labeled carbohydrates to be detected with UV absorbance in standard 50-mu m-i.d. fused silica capillaries by zone electrophoresis. in this mode, nanomolar concentrations of detection limits are obtained. The method for the derivatization. of carbohydrates with NMP is simplified. The derivatization reaction is rapid and mild in the presence of ammonia catalyst without further transfer steps. Nine monosaccharide derivatives such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose and fucose can successfully be detected in CE mode. Good reproducibility can be obtained with relative standard deviation (R.S.D.) values of the migration times and peak area, respectively, from 0.44 to 0.48 and from 3.2 to 4.8. Furthermore, the developed method has been successfully applied to the analysis of carbohydrates in the hydrolyzed rape bee pollen samples. (C) 2008 Published by Elsevier B.V.

A combined DFT and SCRF study of solvent effects on 4-methyl-3-penten-2-one

The IR spectrum of 4-methyl-3-penten-2-one is interpreted with the aid of normal coordinate calculations within the Onsager self-consistent reaction field (SCRF) model, using a density functional theory (DFT) method at the Becke3LYP/6-31G* level. The solvent effects on the geometry, energy, dipole moment, and vibrational frequencies of 4-methyl-3-penten-2-one in the solution and in the liquid phase are calculated using the Onsager SCRF model. The calculated vibrational frequencies in the liquid-phase are in good agreement with the experimental values. The solvent reaction field has generally weak influence. For the two main bands of C=C and C=O mixed vibrational modes, small frequency shifts (5-6 cm(-1)), but relatively large changes in IR intensities (up to 101 km mol(-1) in the liquid phase) are found. (C) 1999 Elsevier Science BV. All rights reserved.

Determination of 1-phenyl-3-methyl-5-pyrazolone-labeled carbohydrates by liquid chromatography and micellar electrokinetic chromatography

In this paper, the method for the derivatization of carbohydrates with 1-phenyl-3-methyl-5-pyrazolone (PMP) was simplified. One-third of the derivatization time was saved. Five monosaccharide derivatives have been well separated by MEKC and HPLC under optimized conditions. Good reproducibility could be obtained with relative standard deviation (RSD) values of the migration times within 5.0 and 2.3%, respectively. Furthermore, the developed methods have been successfully applied to the analysis of carbohydrates in Aloe powder and food. These methods are quite useful for routine analysis of monosaccharides and oligosaccharides in real samples. (C) 2003 Elsevier B.V. All rights reserved.

Solvent extraction of rare earths from chloride medium with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 and sec-octylphenoxyacetic acid

The extraction of rare earth elements from chloride medium by mixtures of sec-nonylphenoxy acetic acid (CA100) with bis(2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex301) or bis(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex302) in n-heptane has been studied. The synergistic enhancement of the extraction of lanthanum (III) by mixtures of CA100 with Cyanex301 has been investigated using the methods of slope analysis and constant mole. The extracted complex of lanthanum (III) is determined. The logarithm of the equilibrium constant is calculated as - 1.41. The formation constants and the thermodynamic functions, Delta H, Delta G, and Delta S have also been determined.

Synergistic extraction of lanthanum(III) from chloride medium by mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 and triisobutylphosphine sulphide

The synergistic effect of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 (HPMBP) and triisobutylphosphine sulphide (TIBPS, B) is investigated in the extraction of lanthanum(III) from chloride solution. Lanthanum(III) is extracted by the mixture as LaCl2.PMBP.B-0.5 instead of La(PMBP)(3).(HPMBP) which is extracted by HPMBP alone. The equilibrium constants and thermodynamic functions such as DeltaG, DeltaH and DeltaS are determined. The extraction of other rare earth ions by mixtures of HPMBP and TIBPS is also studied and the possibility of separating rare earth ions is discussed.